Method of and apparatus for cleaning tubular bodies



, May 17, 1938. H. rl'. BoTToRF 2,117,648

METHOD OF AND APPARATS FOR CLEANING TUBLAR BODIES A Filed Nov. 22. 1955 Patented Mayi 1 7, 1938 UNITED STATES METHOD F AND APPARATUS FOR CLEAN- ING TUBULAR BODIES Harry F. Bottorf,l Williamsport, Pa., assignor to Pangborn Corporation, Hagerstown, Md., a corporation of Maryland Application November 22, 1935, Serial No. 51,174

4 Claims. (Cl. 51-11) This invention relates to methods of, and apparatus for cleaning the inner walls of tubular bodies, and it is more particularly concerned with methods of and apparatus for cleaning comparatively small diameter tube pipes, such as boiler tubes and the like, but it is not limited to such use.

Inthe past, it has been the practice to clean lire-tube boilers with mechanical tools such as scrapers, brushes and the like, or by blowing live steam through the tubes while the boiler is in use. In water tube boilers it has been necessary to take the boiler out of service and scrape the tubes in an effort to remove the scale. These methods, especially in the case of the water tube boiler, are not only laborious but they also fail to efficiently remove the scale and sometimes, especially if Scrapers are used, result in damage to the tubes by reason of the non-uniform internal diameter thereof. Also, with new tubular elements of comparatively small diameter, such Las boiler tubes and the like it has been impossible to efliciently mechanically clean the interior, with the result that costly and time consuming pickling operations have been resorted to.

It is the primary object of this invention to do away with all of the cleaning operations previously used and employ an abrasive blast applied directly against the walls of the tubes.

Another important object of4 this invention is assembly that `is sulciently small'to be intro-` duced into, and advanced through tubes of comparatively small diameter, and that will direct streams of abrasive against the tube walls at angles sufciently great to effect eilicient cleaning thereof. Y

Further objects of'the invention will become Vapparent as the specification proceeds in connection with the annexed drawing, and from the appended claims.

In the drawing: l

Figure 1 isl a' longitudinal sectional view through a 4tube having one formV of nozzle `assembly of the invention, the section through the nozzle -proper being along the line of Figure 2.

Figure 2 is a transverse sectional view taken along the line 2-2 of Figure 1, with the nozzle removed from the tube.

Figure 3 is a View similar to Figure 2, but illustrates a modified form of nozzle also forming part of this invention.

Figures 4 and 5 are fragmental sectional views illustrating further modified-forms of nozzles of this invention, and

Figure 6 is afragmental sectional view of another form of nozzle embodying this invention.

With continued reference to the drawing, whereinJlke reference characters have been employed to designate like parts throughout the several views thereof, and with particular reference to Figures 1 and 2, a tube'IIl is illustrated, and it may be a boiler tube or the like. Tube I0 is supported for cleaning by any suitable means II, which may be a clamping mechanism .if desired; and in the case `of a boiler tube it may constitute the tube sheet itself.

The nozzle assembly is shown in operative position within tube I0 and its comprises a body I2, having a large diameter portion I3 and a preferably integral small diameter portion I4.

Portions I 3 and I4 are connected by a "preferably conical surface portion I5.4 Body I2 is provided with a longitudinal passage I 6, and the part of passage 'in portion I3 functions as an abrasive-air supply conduit, while the portion of passage I6 located in reduced portion I4 is adapted to contain abrasive in static condition, to minimize wear of the parts, as will presently appear.

Communicating with passage I6, and dispos ed at an angle thereto, are a plurality of preferably radial blast jets I1, which are adapted to conduct abrasive from passage I6 and direct it against the inner` wall of tube III, for 4removing scale therefrom.

Blast jets I1 are seen to terminate at inclined surface portion I5, and surface portion I is preferably inclined so as to`be disposed substantially at 90 with respect to the axes of jets I1. The number of jets employed, and the angle that they will assume with respect to passage I E will be determined by lthe particular requirements of the tubes that are to be cleaned. A1- though these values may be varied within certain limits, it has been found that a nozzle employing three or four jets disposed at an angle of approximately 45 to the central passage has given excellent results in tubes having diameters in the neighborhood of two inches.

The abrasive-air blast may be vsupplied to the central passage of body I2 in any suitable manner, but in the present instance a conduit I8 is threaded into a recess I9 in body I2, and a gasket 2| is clamped between the` parts to prevent leakage. Conduit I8 may be connected to any suitable device for supplying an abrasive air mixture thereto, f or instance a machine of the character shown in the application of William A. Rosenberger, Serial No. r110,555, filed February 9, 1934.

If a tube only slightly larger than body I2 is being cleaned, conduit I8 may be of a flexible nature and large diameter portion I3 be relied upon to guide the nozzle assembly within the tube. Conduit I8, however, is preferably of rigid construction, so that the nozzle assembly is positively maintained in substantially parallel relationship to the tube axis at all times, irrespective of the size of the tube.

The nozzle assembly may be employed to clean old or new 'tubes of scale or other undesirable adhering substances. In either case the method preferably employed is as follows:

' The tub is preferably supported in a substantially horizontal position and the nozzle assembly is introduced into one end thereof. The blast is then turned on. When the nozzle is ilrst placed in use, the right hand end of passage I6 fllls up with abrasive approximately to the level of the right-hand edge of jets I1, withthe result that as the abrasive passes through passage I6 and suddenly undergoes a change in direction as it passes is diverted into jets I1, it does not wear the nozzle parts as the bodv of stationary abrasive constitutes th'e diverting wall.

The abrasive issuing from jets I1 strikes the inner wall of tube I0 at an angle oi approximately 45, and eillciently dislodges scale and other adhering material therefrom. As the blasting operation proceeds the nozzle is slowly moved into the tube, with the result that the entire tube surface is progressively cleaned. If desired the nozzle may be rotated while it is being advanced through thetube, but it has been found that good .results are attained when it is held in a ilxed angular position .during the cleaning operation.

While the cleaning operation is being carried out, the strong blast of air accompanying the abrasive effectively blows the removed scale from the tube. This is brought about because of the forward inclination of the blast jets and in small pipes it is also aided -by large diameter portion '|3, which acts as a partial piston, for preventing escape of any large amount of air from the left-hand end of the tube. While the nozzle assembly isl being advanced through the tube large diameter portion I3 may be allowed to ride upon the tube wall, but ii' desired, especially if the tube is of considerably larger diameter than portion I3, conduit I8 may be mounted in guides, so as to support nozzles substantially concentrically with the tube.

The rate of advance of the nozzle assembly through the tube will be determined by the condition of the tube undergoing cleaning. For in-4 ,stance if the tube is unusually dirtythe rate of advance will be lower than if the tube is in a better condition. bIf desired, however, the rate may be maintained constant and differences in' the cleaning required be taken care of by making twol or more passes of the nozzle assembly.

After the tube has been cleaned, the nozzle may be passed through the tube to scavenge it or free it of all traces of abrasive and freed scale particles by shutting off the abrasive supply and merely supplying compressed air to the jets.

, In the nozzle of Figures 1 and 2, jets I1 are symmetrically disposed, with two iets directed upwardly and one downwardly. In some instances, especially where the tube to be cleaned is considerably larger than the nozzle, and the nozzle is allowed to ride upon the tube, it is desirable to arrange the jets in a different relationship. In Figure 3 there is disclosed a nozzle disposed in a larger pipe I Ila, and having three jets I1a, one of which is directed upwardly and two horizontally. The reason for grouping jets I1a in this manneris *to more evenly distribute the abrasive upon the walls and avoid a jet at the point where the nozzle contacts the tube.

In Figures 4 and 5 there are disclosed modified forms of nozzlesl having removable end caps, which may be removed for blowing out the nozzles in case of stoppage. In Figure 4 an end cap 23, provided with a gasket 24, is threaded over the end of small diameter portion Ila of the nozzle. In Figure 5 the end cap assumes the form of a plug 25 equipped with a gasket 26 and it is threaded into small diameter portion Mb of the nozzle.

In Figure 6 there is disclosed a modified form of nozzle I2a, and in this form of the invention jets I1 are preferably four in number and are of larger size. Also a nipple 21 is preferably cast in place with the nozzle. Conduit Il, or a flexible hose, may be threaded onto nipple 21 in any suitable manner.

Although they have not been shown in the drawing, it is to be understood that if desired. passage I6 and/or jets I1 may be equipped with replaceable abrasive resistant liners, and the appended claims are intended to embrace the invention when it assumes this form. Moreover,

vit is preferably constructed in this manner as it may be produced accurately and at low cost. but it is to be lmderstood that it may be made in'two parts if desired. For instance, the nozzle may consist of two parts threadedly connected in the region of-jets- I1 without departing from the spirit of the invention.

In all ofthe forms of the invention disclosed, it is to be understood that the inclination of jets -I1 from the axis of passage I8 may be varied to suit the requirements of the particular tube that is being cleaned, but it is preferably kept within the range of 10 to 80. Moreoven jets I1 may be disposed in planes disposed at angles to the axis oi' passage I6, to impart a swirling action tothe air and abrasive if desired.

The present invention may be embodied in other speciilc forms without departing from the spirit or essential characteristics thereof. The praesent embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indi-v cated by the appended claims rather than by the foregoing descriptiongii and all changes which come within the meaning and range of equivalency of the claims're therefore intended tobe embraced therein.

, Whatis claimed and desired United States Letters Patent 1. In a nozzle assembly for blasting the inner wallsof tubular bodies, an elongated, generally cylindrical member adapt; to be inserted in a tube with its axis parallel the axis of the tube, said member comprising a large diameter portion and a small diameter. portion merging into each other, said large and small diameter portions having a longitudinal passage therein, said passages communicating with each other and being disposed in substantially axially aligned relationship, said large diameter portion having at least one jet therein communicating with the longi- -tudinal passage thereof, said jet terminating at the surface of said member where said large and small diameter portions merge into each other, said jet being operable to direct abrasive against the walls of said tube, and means adapting the longitudinal passage of said large diameter portion for connection to a source of compressed air and abrasive, said large diameter portion having a diameter which is not greatly diierent from` .as boiler tubes and the like, an elongated, generally cylindrical member adapted to be inserted in aftube with its axis parallel to the axis of the tube, said member having a large diameter rear portion and a small ydiameter front portion which each merge into a conical surface provided von said member, said front and rear portions having a longitudinal passage therein, said passage being disposed in substantially axially aligned relationship to the axis of said member, said longitudinal passage terminating at the rear end of said rear portion and openinginto means provided on said member adapting it for connection to a source of compressed air and abrasive, said longitudinal passage terminating at the other end in said front portion, said large diameter portion being of a. diameter which is not material: ly less than the diameter of said tube whereby it may be centered by engagement with the walls of the latter, said rear portion having a plurality of jets provided therein communicating with said longitudinal passage and terminating at said conical surface intermediate said front and rear portions, said jets being disposed obliquely to the axis of said member and adapted to direct abrasive obliquely against the walls of said tube, the portionof said longitudinal passage of said front portion of-said member -dening a closed-ended passage adapted to trap a predetermined quantity of abrasive.

HARRY F. BO'IIORF. 

